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Roadware 10 Minute Concrete Mender™ and Easy-injection mixers make full depth crack repairs in hairline cracks without cutting. This less evasive crack repair technique breaks the rules for concrete repair.

Broken Rule One

Hairline cracks are not worth the trouble fixing.

Broken Rule Two

You have to cut open a hairline crack if you want to actually repair it.

Broken Rule Three

Crack injection requires pumps, ports, slow epoxy, and lots of time.

Lets look at these, “rules” one by one.

Broken Rule One:Hairline cracks are not worth the trouble fixing.Did you know that just about every crack in concrete started out as a hairline crack? Some so fine, you can not even see them with the naked eye. Cracking naturally occurs in concrete slabs as the concrete cures and shrinks. We use saw cut control joins to encourage the concrete to crack inside the saw cut or tooled joints. The problem is, the concrete doesn’t always listen and can crack where it wants to crack. We don’t like it, but that’s just the way it is. The truth is, we would fix hairline cracks if there was a good and efficient way to do it. Most of the time, we ignore hairline cracks and blame them on the nature of concrete and say things like, “It will be fine, you still have aggregate interlock and the crack is just on the surface.” Or, “All concrete cracks, and its just the nature of the product… Check out our new floor covering selection.” The customer, who just invested in a new concrete floor, is never happy with these explanations.

The truth is, we would fix hairline cracks if there was a good and efficient way to do it.

Scoring a concrete crack with a diamond grinder.

Broken Rule Two:You have to cut open crack if you really want to repair it. A repair material has to actually get into a crack so it will actually do some good. Anything short of that is no better than caulk. For the most part, this is true. We can’t repair what we can’t reach. Traditional cut and cover techniques us a diamond blade saw to open up a crack, forming a shallow well for Concrete Mender to accumulate and flow down into the crack. It works really well and Roadware has been doing this for over twenty years.

What is needed is a way to actively push repair products into hairline cracks. With a few simple techniques and Easy Injection Mixers, Roadware 10 Minute Concrete Mender can do the job. That brings us to:

For a successful crack injection repair you need to accomplish three things:

Delivery of materials to the repair area.

The repair material needs to set before if flows away from the repair area .

The repair has to be structurally effective.

Roadware Easy Injection mixers make getting Concrete Mender cracks as small as 20 mil (0.02 inches) simple. Just drill a 3/8 inch hole into the crack and push the nearly water thin Concrete Mender into the cracks. You can actually watch the Concrete Mender flow along the length of the hairline crack. Leave the expensive injection pumps in the shop. A cartridge of Concrete Mender and a manual application gun is all you will need.

Roadware 10 Minute Concrete Mender starts to thicken and cure in about 5 minutes after application, so the material will stay where you put it. Traditional injection epoxies take hours to cure. In many cases, at the end of the day, the epoxy all ends up under the slab and no longer in the crack.

Roadware 10 Minute Concrete Mender™ with Microdoweling™ penetrates traditional bond lines and repairs concrete from the inside out. This structural polyurethane will not become brittle over time. Epoxy injection resins become very hard and brittle. As the the concrete deflects under traffic, the brittle epoxy will start grinding away at the bond-line and the deterioration will start all over again. Roadware 10 Minute Concrete Mender is designed to restore aggregate interlock and deflect with the concrete under heavy traffic and loading. This structural polyurethane will not become brittle over time and is designed to bring the cracked concrete back to original pre-cracked condition.

For many years, engineers have looked for ways to fully inject repair polymers into cracked concrete structures. The general consensus is to seal off the crack with a sacrificial epoxy and install injection ports every few inches. Then thick epoxy is injected under high pressure into the crack with expensive resin injection pumps. The process is time-consuming, the epoxy is brittle, the equipment is expensive and the skill level is highly specialized. This makes epoxy injection slow, expensive and not really effective in the field.

At Roadware, we look for ways to make concrete repair fast, effective and easy.

Fast is better. When injecting Roadware 10 Minute Concrete Mender into concrete, the fast gel and cure time allows you to make a full depth repair from the bottom of the crack up to the top. If the crack you are injecting has a large hidden void, Concrete Mender repairs will start to gel and plug up the void in several minutes. Injection epoxy that takes several hours to cure will sink to the bottom of your crack and pool in the base before it has a chance to cure.

Effective. Concrete Mender is a Structural Polyurethane**. It is about as hard as typical concrete with much greater tensile and bonding strength. It is super thin at 8cps with a surface tension 1/3 of water. It can to penetrate concrete cracks and surfaces. Concrete Mender does not need to be forced into cracks with high pressure pumps and extraordinary methods. Concrete Mender can easily flow into cracks and fissures with just simple manual tools and a specially designed application mixer. You can repair more cracks in less time with less waste then ever before. Repairs are structural in nature and will move with the concrete, not against it like very hard epoxies.

Easy Application. For a repair to be effective in the field, it has to be simple enough for crews to apply efficiently. Installation productivity saves money.

To start, simply drill a 3/8″ diameter hole about one inch deep into the crack at several points along the crack. Clean the crack and holes with a vacuum.* (Click here to learn how to work safely around silica dust).

Tape off the top of the crack and around the holes you just drilled with clear duct tape or Gorilla Clear Repair Tape. These tapes have a good adhesive that will stick to the surrounding concrete. Do not use packing tape or other tapes without testing them first.

Gently squeeze the handle of the gun and slowly inject Concrete Mender into the crack. Work product into several holes at a time, moving the cartridge back and forth among them. Allow time for the Concrete Mender to start gelling in the bottom of the crack. As the crack starts to fill completely, you will see Concrete Mender flow under the clear tape from one drilled hole to the other. You may see air bubbling up from one hole as you inject Concrete Mender into adjacent holes.

Once the crack is filled to refusal, move on to the next few drilled holes until the whole crack is filled.

After 10 minutes at 70 degrees or 23 C, pull the tape. You can use a razor scraper, grinder or polishing device to remove and excess material and blend in the repair.

Drilling a pilot hole into a crack to prepare for injection with Roadware 10 Minute Concrete Mender.

A pilot hole drilled into a concrete crack and ready for injection with Roadware 10 Minute Concrete Mender. Clear repair tape temporarily seals the crack while being repaired.

Roadware 10 Minute Concrete Mender is slowly injected into the crack using a Soft-tip sealing mixer.

Inject Roadware 10 Minute Concrete Mender into the crack until the product appears under the tape. This repairs the crack from the bottom up. Work several holes at a time allowing the product to gel and seal the bottom as you go.

Core drilling of the repair shows full depth repair down 24 inches using this method.

The core sample shows full depth repair down 24 inches.

Concrete Mender repair shown under UV light. See how the Concrete Mender flows into the smallest cracks and brings the concrete back to a pre-cracked condition.

Using Roadware 10 Minute Concrete Mender and Soft-tip injection mixers, you can structurally repair concrete cracks and delaminations with simple tools and methods. This unique system saves time and money and allow for a high production rate for installers. The drill hole/inject method is much less invasive than traditional cut and fill methods and creates a lot less silica dust on the jobsite. The Microdoweling properties of Concrete Mender and Soft-tip Injection promises to be a winning combination for tough concrete repair challenges.

80300 Roadware 10 Minute Concrete Mender 600ml Cartridge

80300 Roadware 10 Minute Concrete Mender 600ml Cartridge

1006-STR 24-element static mixer with Easy Injection Tip

1006-STR 24-element static mixer with Easy Injection Tip

*“Workers may be exposed to dangerous levels of silica dust when cutting, drilling, grinding, or otherwise disturbing materials that contain silica. These materials and tasks are common on construction jobs. Breathing that dust can lead to serious, often fatal illnesses.” The Center for Construction Research and Training. Click here to learn how to work safely with silica.

** Structural Polyurethane: A polyurethane based material that restores structural integrity and aggregate interlock to distressed concrete by using low surface tension and low viscosity to penetrate concrete surfaces and cross-linking polymer chains to bond directly to the concrete-aggregate matrix. This bonding action utilizes capillary forces to self-inject polymer chains into the surrounding concrete. This material should have a modulus of elasticity less than the surrounding concrete and should not become brittle over time. This material may be combined with manufactured sand to form a PCC compatible polymer concrete that can structurally repair concrete cracks and spalls.

Question: How do you epoxy inject cracks in floor slabs on grade when you do not have access to the bottom of the slab? What keeps the product from running out the bottom and all over the place?Answer: We make these type of repairs all the time. The first thing to do is dump the epoxy. It is too thick, too brittle, and takes too long to set. Fast setting materials like 10 Minute Concrete Mender allow you to control set points deep in the crack and prevent material seepage.Roadware 10 Minute Concrete Mender™ has an ultra low viscosity of 8cps and will gravity inject into the smallest of cracks. We make the repair in stages adding fine silica sand into the crack as necessary to prevent the material from running out the bottom. The product can be injected with needle tip mixers as small as 18 gauge. With careful technique and experience you can make structural repair that will restore aggregate interlock and restore the slab.

Start out by adding a small amount Concrete Mender to the prepared crack and noting where material in running beyond the slab. Add a light dusting of silica sand or fine quartz to the crack and some more Concrete Mender. The Concrete Mender will combined with the particles of sand to form a quick setting, “mud” at the bottom of the crack. Repeat as necessary and repair the full depth of the slab.

This will be a structural repair with no ports, no pumps, and almost no down time.

For the first time, Roadware 10 Minute Concrete Mender™, the industry’s only Microdoweling™ concrete repair polyurethane, is available in 50ml mini cartridges. The mini cartridge offers precise application control that is perfect for repairing hairline cracks. Each mini cartridge comes with a needle tip mixer and is simple to use. Use the 50 ml cartridge with the Roadware 5150 application tool. Each cartridge will repair about 10 feet of hairline cracks or 3 feet of 1/4 x 1/4 inch cracks.

Roadware delimanition repairs are featured in the July 2008 issue of Concrete International. This is the official publication of the American Concrete Institute. The article was written by Nelson Tonet, President of Express Polymers and a Roadware distributor.

ABSTRACT
“Delaminations in concrete floor slabs can be difficult to repair in a cost-effective and timely manner. A newly developed product (Roadware 10 Minute Concrete Mender™) that uses a two-part hybrid polyurethane with a viscosity similar to water can significantly reduce the difficulty of performing delamination repairs by easily flowing up to 10 ft (3 m) from an injection point and penetrating deep into concrete surfaces. The product also speeds up repair by setting in only 10 minutes, allowing the repair to be checked by sounding only 30 minutes after product placement.”

Roadware 10 Minute Concrete Mender™ is an excellent choice for repairing concrete slab delaminations. The very low viscosity of less then 8 cps and the exclusive Microdoweling™ penetration properties of the material allow it to flow deep into delaminated concrete voids. The Concrete Mender will restore aggregate interlock and will allow dynamic load transfer under heavy traffic. The expense and mess of pressure injection with epoxy can be avoided.

Two methods of repair have been successful. The first involved dry diamond drilling a 2 or 3 inch (5-8 cm) diameter hole into the concrete slab down to the delamination. Dust is removed with a shop vacuum. Roadware 10 Minute Concrete Mender is poured or pumped into the void. Only one or two inches (3-5 cm) of head pressure is required to push the material as far as 10 ft (3 m) into the delamination. When the material backs up to the top of the hole and the void is filled, silica sand is added and the hole is filled flush with the surface. Soundings are made with a hammer to verify the delamination is repaired in about 30 minutes after application.

Another method is to drill multiple 3/8 inch (1 cm) holes into the concrete down to the delamination. Remove dust with a shop vacuum and inject pre-mixed Roadware 10 Minute Concrete Mender™ with a syringe tipped with a rubber gasket. With this method, you can actually see the material exit the adjacent hole and verify the material is filling the delaminated area. After filling, the holes are blended into the surrounding concrete with silica sand and Concrete Mender or re-drill 1/4″ (5 mm) deep and fill with a color matching concrete mortar.

See the movie:

Both methods will yield good results and are more cost effective than epoxy injection.

The same Microdoweling™ properties of Roadware 10 Minute Concrete Mender™ that make the material excellent for repairing horizontal surfaces also make a good choice for vertical repairs.

UPDATE: New method recommended for vertical crack repair. See the Gebbie System.

Roadware 10 Minute Concrete Mender™ is a very low viscosity polyurethane that uses a surface tension one-third of water to penetrate quickly and deeply into concrete cracks. The typical process relies on self-gravity injection to fill cracks completely. What is not seen by the naked eye is the capillary action of the Concrete Mender polymer chains flowing horizontally into the sidewalls of the crack. We call this chaining of polymers into the concrete Microdoweling™. This chaining of the concrete together works on vertical surfaces too.

So, your saying, “How do we get this super thin material to stay in place long enough for the Microdoweling™ to take place and the repair to cure?” Over the years, Roadware contractors have come up with creative and ingenious ways to use Roadware 10 Minute Concrete Mender™ on vertical surfaces. Here are some techniques that have evolved.

UPDATE: New method recommended for vertical crack repair. See the Gebbie System.

1. Vertical Crack Injection

This technique involves covering the vertical crack with transparent duct tape and injecting Concrete Mender through the tape with a needle tip meter/mix cartridge. This method will work well if the concrete surface is smooth and the tape can make a good bond with the surface. The crack should be 1/4 inch (5mm) or less in width. The tape will make the, “form” while the Concrete Mender sets. Concrete Mender will not stick to duct tape, so once the material cures, you can cleanly pull off the tape. It is best to warm the cartridges up to 80° F (26°C) before use for a faster gel time. Start filling the crack at the lowest point and work you way up.

See the video here.

2. Bulk Mix and Trowel Applied Repair

Mix bulk Concrete Mender and 60-80 grit manufactured sand into a thick mortar. Working in small batches, use a margin trowel to make the repair. The fine sand will hold the Concrete Mender in place long enough for the Microdoweling™ effect to take place and for the material to set.

3. Bag Mix and Apply

This method uses a heavy duty, clear plastic bag to quickly mix one part of blended Concrete Mender to two parts of 60-80 grit manufactured sand. Once mixed by kneading the bag for several seconds, the bag is opened and the whole batch is applied and held in place with the bag. This technique is used around building mechanical entry points such as refrigeration and HVAC units.

Whatever method you choose, Roadware 10 Minute Concrete Mender™ stands at the ready to perform. Finished repairs can be ground smooth and painted to match the wall if necessary.

In March, you donated the Roadware kit to bind the cracks at the Hope Alive! Clinic in Haiti. THANK YOU FOR YOUR GIVING AND KIND HEART.

We went to the Atlantic City airport with the msds. They refused to allow us to bring the tubes on the plane. (they really didn’t know how to read the msds sheets either)

Anyway, we shipped the package via Philadelphia-container-Haiti. It arrived in time for our July 8th trip.

We brought along a Pastor who is also a “concrete guy”. He stated that he had never worked with a product that was so easy and did such a great job. As you can see in the attached photos, the fissure is completely sealed. As I mentioned in our phone conversation, the epi-center of the quake was only 6-7 miles from our clinic. We even have 2 sets of tubes left over!! (the neighbors will benefit)

I do not know how to say thanks but to just say “thanks” . Your kindness has made a difference with Hope Alive Clinics and the Haitian people. visit www.hopealiveclinic.org for more pictures of the teams and clinic activities.

Roadware 10 Minute Concrete Mender™ is an excellent choice for repairing full depth concrete slab cracks. The very low viscosity of less than 8 cps and the exclusive Microdoweling™ penetration properties of the material allow it to flow deep into cracks. The procedure below illustrates Microdoweling™ in action. The Concrete Mender will restore aggregate interlock and will allow dynamic load transfer under heavy traffic. The expense and mess of pressure injection with epoxy can be avoided.Here is a parking deck project located in the North Eastern United States. Hairline cracks run 9-12 inches deep through the deck slab. The contractor drilled 1 1/2 inch holes, 2-3 inches deep into the hairline cracks approximately every 18 inches. Inspection from the floor below reveals full penetration without pumps or ports. Engineers tell us that Roadware Microdoweling™ is quicker and more cost effective than epoxy injection. The results speak for themselves.